When removing loads from a roller conveyor, it is usually desirable to prevent the entire run of loads from bearing against the lead load at the discharge end of the conveyor so that the lead load can be easily removed. Various types of load spacing mechanisms have been used in the past for separating the lead load from the remaining loads on the conveyor. In one type of device, an actuating lever is connected by mechanical means to a stop mechanism. When the lead load is positioned over the actuating lever, it depresses the actuating lever and causes the stop mechanism to extend upwardly into the path of the next adjacent load. When the lead load is removed from the end of the conveyor, the actuating lever returns to an extended position and the stop mechanism is retracted to allow the next successive load to move down the conveyor. One mechanism of this type is disclosed in the patent vom Stein, U.S. Pat. No. 4,646,909 which issued on Mar. 3, 1987.
Several drawbacks have been encountered with these prior art load separating mechanisms. One problem is the inadvertent release of the second load in line before the lead load is removed from the conveyor. This problem is sometimes encountered when the loads are conveyed on pallets. The load-carrying pallets do not always have a continuous bottom surface, but instead may have several cross boards extending across the bottom of the pallet. In this case, it is possible for the actuating lever to return to its upright position between the cross boards of the pallet causing the second load to be released before the lead load has been removed.
Another drawback associated with prior art load separating mechanisms is that the loads are released too quickly after a pallet is removed. The worker responsible for removing loads from the conveyor must have sufficient time to fully remove and dispose of the loads before the next load is released. In prior art load-separating mechanisms, the next load is released immediately as the lead load is lifted or partially removed from the discharge end of the conveyor.